The Fotga DP500IIS FF that's sold on this forum is very good, I'll be using mine and the Hondo $50FF depending on how skeletal I want the rig to be. Both are comparatively very lightweight, very affordable, and precise. For a shoulder rig, though, I don't usually use a follow focus as my hand rarely leaves the lens - I shoot more ENG style and that gives me extra stability.

I can't speak to clip-on matteboxes but I do recommend any of the lighter weight rail-mount dslr boxes (Fotga again, Lanparte, etc.) - if you can get a 3x3 instead you'll save weight and money on filters, but it may not cover the widest lenses. I run a 4x4, often without flags, and have not had any problems. Since you'll need rails for the FF there's not really any reason to run a clip-on in my opinion, as you'll have to switch matteboxes when changing lenses and that's just another thing to have to deal with. But there's nothing wrong with them either, and they let you run without rails when you want to. Again, for weight I'd suggest 3x3 in that case.

Thank you StudioDCCreative. Hadn't really looked into 3x3 filters. Thank you mrbill... after a cursory glance, I wasn't finding what I was looking for, but should definitely dig deeper!

Thank you, PierreB!